/***********************************************************************

	$Id: gstaes256.c,v 1.2 2016/09/05 14:03:03 warme Exp $

	File:	gstaes256.c
	Rev:	e-1
	Date:	09/05/2016

	Copyright (c) 2002, 2016 by David M. Warme.  This work is
	licensed under a Creative Commons Attribution
	4.0 International License.

************************************************************************

	Implementation of AES-256 cipher.

************************************************************************

	Modification Log:

	e-1:	09/05/2016	warme
		: Created.

************************************************************************/

#include "gstaes256.h"

#include "logic.h"

void		_gst_aes256_clear (struct _gst_aes256_context * context);
void		_gst_aes256_decrypt_ecb (
				struct _gst_aes256_context *	context,
				int8u *				buffer);
void		_gst_aes256_encrypt_ecb (
				struct _gst_aes256_context *	context,
				int8u *				buffer);
void		_gst_aes256_init (struct _gst_aes256_context *	context,
				  const int8u *			key);

static inline void	aes256_AddRoundKey (int8u * buffer, const int8u * key);
static inline void	aes256_AddRoundKey_and_copy (
					int8u *		buffer,
					const int8u *	key,
					int8u *		key_copy);
static inline void	aes256_ExpandDecryptionKey (int8u *	key,
						    int8u *	buffer);
static inline void	aes256_ExpandEncryptionKey (int8u *	key,
						    int8u *	buffer);
static inline void	aes256_MixColumns (int8u * buffer);
static inline void	aes256_ShiftRows (int8u * buffer);
static inline void	aes256_SubBytes (int8u * buffer);
static inline void	aes256_inverse_MixColumns (int8u * buffer);
static inline void	aes256_inverse_ShiftRows (int8u * buffer);
static inline void	aes256_inverse_SubBytes (int8u * buffer);
static inline int8u	rijndael_times_x (int8u poly);
static inline int8u	rijndael_times_x_inverse (int8u poly);
static inline int8u	update_rcon_decrypt (int8u rcon);
static inline int8u	update_rcon_encrypt (int8u rcon);

/*
 * The Rijndael S-box, and its inverse.
 */

static const int8u		rijndael_sbox [256] = {
	0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5,
	0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76,
	0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0,
	0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0,
	0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC,
	0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15,
	0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A,
	0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75,
	0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0,
	0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84,
	0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B,
	0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF,
	0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85,
	0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8,
	0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5,
	0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2,
	0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17,
	0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73,
	0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88,
	0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB,
	0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C,
	0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79,
	0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9,
	0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08,
	0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6,
	0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A,
	0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E,
	0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E,
	0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94,
	0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF,
	0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68,
	0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16
};

static const int8u	rijndael_inverse_sbox [256] = {
	0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38,
	0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB,
	0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87,
	0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB,
	0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D,
	0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E,
	0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2,
	0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25,
	0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16,
	0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92,
	0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA,
	0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84,
	0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A,
	0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06,
	0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02,
	0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B,
	0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA,
	0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73,
	0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85,
	0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E,
	0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89,
	0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B,
	0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20,
	0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4,
	0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31,
	0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F,
	0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D,
	0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF,
	0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0,
	0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61,
	0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26,
	0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D
};

/*
 * Tables to multiply by various constants within Rijndael's Galois field.
 */

static const int8u	rijndael_times_2 [256] = {
	0x00, 0x02, 0x04, 0x06, 0x08, 0x0A, 0x0C, 0x0E,
	0x10, 0x12, 0x14, 0x16, 0x18, 0x1A, 0x1C, 0x1E,
	0x20, 0x22, 0x24, 0x26, 0x28, 0x2A, 0x2C, 0x2E,
	0x30, 0x32, 0x34, 0x36, 0x38, 0x3A, 0x3C, 0x3E,
	0x40, 0x42, 0x44, 0x46, 0x48, 0x4A, 0x4C, 0x4E,
	0x50, 0x52, 0x54, 0x56, 0x58, 0x5A, 0x5C, 0x5E,
	0x60, 0x62, 0x64, 0x66, 0x68, 0x6A, 0x6C, 0x6E,
	0x70, 0x72, 0x74, 0x76, 0x78, 0x7A, 0x7C, 0x7E,
	0x80, 0x82, 0x84, 0x86, 0x88, 0x8A, 0x8C, 0x8E,
	0x90, 0x92, 0x94, 0x96, 0x98, 0x9A, 0x9C, 0x9E,
	0xA0, 0xA2, 0xA4, 0xA6, 0xA8, 0xAA, 0xAC, 0xAE,
	0xB0, 0xB2, 0xB4, 0xB6, 0xB8, 0xBA, 0xBC, 0xBE,
	0xC0, 0xC2, 0xC4, 0xC6, 0xC8, 0xCA, 0xCC, 0xCE,
	0xD0, 0xD2, 0xD4, 0xD6, 0xD8, 0xDA, 0xDC, 0xDE,
	0xE0, 0xE2, 0xE4, 0xE6, 0xE8, 0xEA, 0xEC, 0xEE,
	0xF0, 0xF2, 0xF4, 0xF6, 0xF8, 0xFA, 0xFC, 0xFE,
	0x1B, 0x19, 0x1F, 0x1D, 0x13, 0x11, 0x17, 0x15,
	0x0B, 0x09, 0x0F, 0x0D, 0x03, 0x01, 0x07, 0x05,
	0x3B, 0x39, 0x3F, 0x3D, 0x33, 0x31, 0x37, 0x35,
	0x2B, 0x29, 0x2F, 0x2D, 0x23, 0x21, 0x27, 0x25,
	0x5B, 0x59, 0x5F, 0x5D, 0x53, 0x51, 0x57, 0x55,
	0x4B, 0x49, 0x4F, 0x4D, 0x43, 0x41, 0x47, 0x45,
	0x7B, 0x79, 0x7F, 0x7D, 0x73, 0x71, 0x77, 0x75,
	0x6B, 0x69, 0x6F, 0x6D, 0x63, 0x61, 0x67, 0x65,
	0x9B, 0x99, 0x9F, 0x9D, 0x93, 0x91, 0x97, 0x95,
	0x8B, 0x89, 0x8F, 0x8D, 0x83, 0x81, 0x87, 0x85,
	0xBB, 0xB9, 0xBF, 0xBD, 0xB3, 0xB1, 0xB7, 0xB5,
	0xAB, 0xA9, 0xAF, 0xAD, 0xA3, 0xA1, 0xA7, 0xA5,
	0xDB, 0xD9, 0xDF, 0xDD, 0xD3, 0xD1, 0xD7, 0xD5,
	0xCB, 0xC9, 0xCF, 0xCD, 0xC3, 0xC1, 0xC7, 0xC5,
	0xFB, 0xF9, 0xFF, 0xFD, 0xF3, 0xF1, 0xF7, 0xF5,
	0xEB, 0xE9, 0xEF, 0xED, 0xE3, 0xE1, 0xE7, 0xE5
};

static const int8u	rijndael_times_3 [256] = {
	0x00, 0x03, 0x06, 0x05, 0x0C, 0x0F, 0x0A, 0x09,
	0x18, 0x1B, 0x1E, 0x1D, 0x14, 0x17, 0x12, 0x11,
	0x30, 0x33, 0x36, 0x35, 0x3C, 0x3F, 0x3A, 0x39,
	0x28, 0x2B, 0x2E, 0x2D, 0x24, 0x27, 0x22, 0x21,
	0x60, 0x63, 0x66, 0x65, 0x6C, 0x6F, 0x6A, 0x69,
	0x78, 0x7B, 0x7E, 0x7D, 0x74, 0x77, 0x72, 0x71,
	0x50, 0x53, 0x56, 0x55, 0x5C, 0x5F, 0x5A, 0x59,
	0x48, 0x4B, 0x4E, 0x4D, 0x44, 0x47, 0x42, 0x41,
	0xC0, 0xC3, 0xC6, 0xC5, 0xCC, 0xCF, 0xCA, 0xC9,
	0xD8, 0xDB, 0xDE, 0xDD, 0xD4, 0xD7, 0xD2, 0xD1,
	0xF0, 0xF3, 0xF6, 0xF5, 0xFC, 0xFF, 0xFA, 0xF9,
	0xE8, 0xEB, 0xEE, 0xED, 0xE4, 0xE7, 0xE2, 0xE1,
	0xA0, 0xA3, 0xA6, 0xA5, 0xAC, 0xAF, 0xAA, 0xA9,
	0xB8, 0xBB, 0xBE, 0xBD, 0xB4, 0xB7, 0xB2, 0xB1,
	0x90, 0x93, 0x96, 0x95, 0x9C, 0x9F, 0x9A, 0x99,
	0x88, 0x8B, 0x8E, 0x8D, 0x84, 0x87, 0x82, 0x81,
	0x9B, 0x98, 0x9D, 0x9E, 0x97, 0x94, 0x91, 0x92,
	0x83, 0x80, 0x85, 0x86, 0x8F, 0x8C, 0x89, 0x8A,
	0xAB, 0xA8, 0xAD, 0xAE, 0xA7, 0xA4, 0xA1, 0xA2,
	0xB3, 0xB0, 0xB5, 0xB6, 0xBF, 0xBC, 0xB9, 0xBA,
	0xFB, 0xF8, 0xFD, 0xFE, 0xF7, 0xF4, 0xF1, 0xF2,
	0xE3, 0xE0, 0xE5, 0xE6, 0xEF, 0xEC, 0xE9, 0xEA,
	0xCB, 0xC8, 0xCD, 0xCE, 0xC7, 0xC4, 0xC1, 0xC2,
	0xD3, 0xD0, 0xD5, 0xD6, 0xDF, 0xDC, 0xD9, 0xDA,
	0x5B, 0x58, 0x5D, 0x5E, 0x57, 0x54, 0x51, 0x52,
	0x43, 0x40, 0x45, 0x46, 0x4F, 0x4C, 0x49, 0x4A,
	0x6B, 0x68, 0x6D, 0x6E, 0x67, 0x64, 0x61, 0x62,
	0x73, 0x70, 0x75, 0x76, 0x7F, 0x7C, 0x79, 0x7A,
	0x3B, 0x38, 0x3D, 0x3E, 0x37, 0x34, 0x31, 0x32,
	0x23, 0x20, 0x25, 0x26, 0x2F, 0x2C, 0x29, 0x2A,
	0x0B, 0x08, 0x0D, 0x0E, 0x07, 0x04, 0x01, 0x02,
	0x13, 0x10, 0x15, 0x16, 0x1F, 0x1C, 0x19, 0x1A
};

static const int8u	rijndael_times_9 [256] = {
	0x00, 0x09, 0x12, 0x1B, 0x24, 0x2D, 0x36, 0x3F,
	0x48, 0x41, 0x5A, 0x53, 0x6C, 0x65, 0x7E, 0x77,
	0x90, 0x99, 0x82, 0x8B, 0xB4, 0xBD, 0xA6, 0xAF,
	0xD8, 0xD1, 0xCA, 0xC3, 0xFC, 0xF5, 0xEE, 0xE7,
	0x3B, 0x32, 0x29, 0x20, 0x1F, 0x16, 0x0D, 0x04,
	0x73, 0x7A, 0x61, 0x68, 0x57, 0x5E, 0x45, 0x4C,
	0xAB, 0xA2, 0xB9, 0xB0, 0x8F, 0x86, 0x9D, 0x94,
	0xE3, 0xEA, 0xF1, 0xF8, 0xC7, 0xCE, 0xD5, 0xDC,
	0x76, 0x7F, 0x64, 0x6D, 0x52, 0x5B, 0x40, 0x49,
	0x3E, 0x37, 0x2C, 0x25, 0x1A, 0x13, 0x08, 0x01,
	0xE6, 0xEF, 0xF4, 0xFD, 0xC2, 0xCB, 0xD0, 0xD9,
	0xAE, 0xA7, 0xBC, 0xB5, 0x8A, 0x83, 0x98, 0x91,
	0x4D, 0x44, 0x5F, 0x56, 0x69, 0x60, 0x7B, 0x72,
	0x05, 0x0C, 0x17, 0x1E, 0x21, 0x28, 0x33, 0x3A,
	0xDD, 0xD4, 0xCF, 0xC6, 0xF9, 0xF0, 0xEB, 0xE2,
	0x95, 0x9C, 0x87, 0x8E, 0xB1, 0xB8, 0xA3, 0xAA,
	0xEC, 0xE5, 0xFE, 0xF7, 0xC8, 0xC1, 0xDA, 0xD3,
	0xA4, 0xAD, 0xB6, 0xBF, 0x80, 0x89, 0x92, 0x9B,
	0x7C, 0x75, 0x6E, 0x67, 0x58, 0x51, 0x4A, 0x43,
	0x34, 0x3D, 0x26, 0x2F, 0x10, 0x19, 0x02, 0x0B,
	0xD7, 0xDE, 0xC5, 0xCC, 0xF3, 0xFA, 0xE1, 0xE8,
	0x9F, 0x96, 0x8D, 0x84, 0xBB, 0xB2, 0xA9, 0xA0,
	0x47, 0x4E, 0x55, 0x5C, 0x63, 0x6A, 0x71, 0x78,
	0x0F, 0x06, 0x1D, 0x14, 0x2B, 0x22, 0x39, 0x30,
	0x9A, 0x93, 0x88, 0x81, 0xBE, 0xB7, 0xAC, 0xA5,
	0xD2, 0xDB, 0xC0, 0xC9, 0xF6, 0xFF, 0xE4, 0xED,
	0x0A, 0x03, 0x18, 0x11, 0x2E, 0x27, 0x3C, 0x35,
	0x42, 0x4B, 0x50, 0x59, 0x66, 0x6F, 0x74, 0x7D,
	0xA1, 0xA8, 0xB3, 0xBA, 0x85, 0x8C, 0x97, 0x9E,
	0xE9, 0xE0, 0xFB, 0xF2, 0xCD, 0xC4, 0xDF, 0xD6,
	0x31, 0x38, 0x23, 0x2A, 0x15, 0x1C, 0x07, 0x0E,
	0x79, 0x70, 0x6B, 0x62, 0x5D, 0x54, 0x4F, 0x46
};

static const int8u	rijndael_times_11 [256] = {
	0x00, 0x0B, 0x16, 0x1D, 0x2C, 0x27, 0x3A, 0x31,
	0x58, 0x53, 0x4E, 0x45, 0x74, 0x7F, 0x62, 0x69,
	0xB0, 0xBB, 0xA6, 0xAD, 0x9C, 0x97, 0x8A, 0x81,
	0xE8, 0xE3, 0xFE, 0xF5, 0xC4, 0xCF, 0xD2, 0xD9,
	0x7B, 0x70, 0x6D, 0x66, 0x57, 0x5C, 0x41, 0x4A,
	0x23, 0x28, 0x35, 0x3E, 0x0F, 0x04, 0x19, 0x12,
	0xCB, 0xC0, 0xDD, 0xD6, 0xE7, 0xEC, 0xF1, 0xFA,
	0x93, 0x98, 0x85, 0x8E, 0xBF, 0xB4, 0xA9, 0xA2,
	0xF6, 0xFD, 0xE0, 0xEB, 0xDA, 0xD1, 0xCC, 0xC7,
	0xAE, 0xA5, 0xB8, 0xB3, 0x82, 0x89, 0x94, 0x9F,
	0x46, 0x4D, 0x50, 0x5B, 0x6A, 0x61, 0x7C, 0x77,
	0x1E, 0x15, 0x08, 0x03, 0x32, 0x39, 0x24, 0x2F,
	0x8D, 0x86, 0x9B, 0x90, 0xA1, 0xAA, 0xB7, 0xBC,
	0xD5, 0xDE, 0xC3, 0xC8, 0xF9, 0xF2, 0xEF, 0xE4,
	0x3D, 0x36, 0x2B, 0x20, 0x11, 0x1A, 0x07, 0x0C,
	0x65, 0x6E, 0x73, 0x78, 0x49, 0x42, 0x5F, 0x54,
	0xF7, 0xFC, 0xE1, 0xEA, 0xDB, 0xD0, 0xCD, 0xC6,
	0xAF, 0xA4, 0xB9, 0xB2, 0x83, 0x88, 0x95, 0x9E,
	0x47, 0x4C, 0x51, 0x5A, 0x6B, 0x60, 0x7D, 0x76,
	0x1F, 0x14, 0x09, 0x02, 0x33, 0x38, 0x25, 0x2E,
	0x8C, 0x87, 0x9A, 0x91, 0xA0, 0xAB, 0xB6, 0xBD,
	0xD4, 0xDF, 0xC2, 0xC9, 0xF8, 0xF3, 0xEE, 0xE5,
	0x3C, 0x37, 0x2A, 0x21, 0x10, 0x1B, 0x06, 0x0D,
	0x64, 0x6F, 0x72, 0x79, 0x48, 0x43, 0x5E, 0x55,
	0x01, 0x0A, 0x17, 0x1C, 0x2D, 0x26, 0x3B, 0x30,
	0x59, 0x52, 0x4F, 0x44, 0x75, 0x7E, 0x63, 0x68,
	0xB1, 0xBA, 0xA7, 0xAC, 0x9D, 0x96, 0x8B, 0x80,
	0xE9, 0xE2, 0xFF, 0xF4, 0xC5, 0xCE, 0xD3, 0xD8,
	0x7A, 0x71, 0x6C, 0x67, 0x56, 0x5D, 0x40, 0x4B,
	0x22, 0x29, 0x34, 0x3F, 0x0E, 0x05, 0x18, 0x13,
	0xCA, 0xC1, 0xDC, 0xD7, 0xE6, 0xED, 0xF0, 0xFB,
	0x92, 0x99, 0x84, 0x8F, 0xBE, 0xB5, 0xA8, 0xA3
};

static const int8u	rijndael_times_13 [256] = {
	0x00, 0x0D, 0x1A, 0x17, 0x34, 0x39, 0x2E, 0x23,
	0x68, 0x65, 0x72, 0x7F, 0x5C, 0x51, 0x46, 0x4B,
	0xD0, 0xDD, 0xCA, 0xC7, 0xE4, 0xE9, 0xFE, 0xF3,
	0xB8, 0xB5, 0xA2, 0xAF, 0x8C, 0x81, 0x96, 0x9B,
	0xBB, 0xB6, 0xA1, 0xAC, 0x8F, 0x82, 0x95, 0x98,
	0xD3, 0xDE, 0xC9, 0xC4, 0xE7, 0xEA, 0xFD, 0xF0,
	0x6B, 0x66, 0x71, 0x7C, 0x5F, 0x52, 0x45, 0x48,
	0x03, 0x0E, 0x19, 0x14, 0x37, 0x3A, 0x2D, 0x20,
	0x6D, 0x60, 0x77, 0x7A, 0x59, 0x54, 0x43, 0x4E,
	0x05, 0x08, 0x1F, 0x12, 0x31, 0x3C, 0x2B, 0x26,
	0xBD, 0xB0, 0xA7, 0xAA, 0x89, 0x84, 0x93, 0x9E,
	0xD5, 0xD8, 0xCF, 0xC2, 0xE1, 0xEC, 0xFB, 0xF6,
	0xD6, 0xDB, 0xCC, 0xC1, 0xE2, 0xEF, 0xF8, 0xF5,
	0xBE, 0xB3, 0xA4, 0xA9, 0x8A, 0x87, 0x90, 0x9D,
	0x06, 0x0B, 0x1C, 0x11, 0x32, 0x3F, 0x28, 0x25,
	0x6E, 0x63, 0x74, 0x79, 0x5A, 0x57, 0x40, 0x4D,
	0xDA, 0xD7, 0xC0, 0xCD, 0xEE, 0xE3, 0xF4, 0xF9,
	0xB2, 0xBF, 0xA8, 0xA5, 0x86, 0x8B, 0x9C, 0x91,
	0x0A, 0x07, 0x10, 0x1D, 0x3E, 0x33, 0x24, 0x29,
	0x62, 0x6F, 0x78, 0x75, 0x56, 0x5B, 0x4C, 0x41,
	0x61, 0x6C, 0x7B, 0x76, 0x55, 0x58, 0x4F, 0x42,
	0x09, 0x04, 0x13, 0x1E, 0x3D, 0x30, 0x27, 0x2A,
	0xB1, 0xBC, 0xAB, 0xA6, 0x85, 0x88, 0x9F, 0x92,
	0xD9, 0xD4, 0xC3, 0xCE, 0xED, 0xE0, 0xF7, 0xFA,
	0xB7, 0xBA, 0xAD, 0xA0, 0x83, 0x8E, 0x99, 0x94,
	0xDF, 0xD2, 0xC5, 0xC8, 0xEB, 0xE6, 0xF1, 0xFC,
	0x67, 0x6A, 0x7D, 0x70, 0x53, 0x5E, 0x49, 0x44,
	0x0F, 0x02, 0x15, 0x18, 0x3B, 0x36, 0x21, 0x2C,
	0x0C, 0x01, 0x16, 0x1B, 0x38, 0x35, 0x22, 0x2F,
	0x64, 0x69, 0x7E, 0x73, 0x50, 0x5D, 0x4A, 0x47,
	0xDC, 0xD1, 0xC6, 0xCB, 0xE8, 0xE5, 0xF2, 0xFF,
	0xB4, 0xB9, 0xAE, 0xA3, 0x80, 0x8D, 0x9A, 0x97
};

static const int8u	rijndael_times_14 [256] = {
	0x00, 0x0E, 0x1C, 0x12, 0x38, 0x36, 0x24, 0x2A,
	0x70, 0x7E, 0x6C, 0x62, 0x48, 0x46, 0x54, 0x5A,
	0xE0, 0xEE, 0xFC, 0xF2, 0xD8, 0xD6, 0xC4, 0xCA,
	0x90, 0x9E, 0x8C, 0x82, 0xA8, 0xA6, 0xB4, 0xBA,
	0xDB, 0xD5, 0xC7, 0xC9, 0xE3, 0xED, 0xFF, 0xF1,
	0xAB, 0xA5, 0xB7, 0xB9, 0x93, 0x9D, 0x8F, 0x81,
	0x3B, 0x35, 0x27, 0x29, 0x03, 0x0D, 0x1F, 0x11,
	0x4B, 0x45, 0x57, 0x59, 0x73, 0x7D, 0x6F, 0x61,
	0xAD, 0xA3, 0xB1, 0xBF, 0x95, 0x9B, 0x89, 0x87,
	0xDD, 0xD3, 0xC1, 0xCF, 0xE5, 0xEB, 0xF9, 0xF7,
	0x4D, 0x43, 0x51, 0x5F, 0x75, 0x7B, 0x69, 0x67,
	0x3D, 0x33, 0x21, 0x2F, 0x05, 0x0B, 0x19, 0x17,
	0x76, 0x78, 0x6A, 0x64, 0x4E, 0x40, 0x52, 0x5C,
	0x06, 0x08, 0x1A, 0x14, 0x3E, 0x30, 0x22, 0x2C,
	0x96, 0x98, 0x8A, 0x84, 0xAE, 0xA0, 0xB2, 0xBC,
	0xE6, 0xE8, 0xFA, 0xF4, 0xDE, 0xD0, 0xC2, 0xCC,
	0x41, 0x4F, 0x5D, 0x53, 0x79, 0x77, 0x65, 0x6B,
	0x31, 0x3F, 0x2D, 0x23, 0x09, 0x07, 0x15, 0x1B,
	0xA1, 0xAF, 0xBD, 0xB3, 0x99, 0x97, 0x85, 0x8B,
	0xD1, 0xDF, 0xCD, 0xC3, 0xE9, 0xE7, 0xF5, 0xFB,
	0x9A, 0x94, 0x86, 0x88, 0xA2, 0xAC, 0xBE, 0xB0,
	0xEA, 0xE4, 0xF6, 0xF8, 0xD2, 0xDC, 0xCE, 0xC0,
	0x7A, 0x74, 0x66, 0x68, 0x42, 0x4C, 0x5E, 0x50,
	0x0A, 0x04, 0x16, 0x18, 0x32, 0x3C, 0x2E, 0x20,
	0xEC, 0xE2, 0xF0, 0xFE, 0xD4, 0xDA, 0xC8, 0xC6,
	0x9C, 0x92, 0x80, 0x8E, 0xA4, 0xAA, 0xB8, 0xB6,
	0x0C, 0x02, 0x10, 0x1E, 0x34, 0x3A, 0x28, 0x26,
	0x7C, 0x72, 0x60, 0x6E, 0x44, 0x4A, 0x58, 0x56,
	0x37, 0x39, 0x2B, 0x25, 0x0F, 0x01, 0x13, 0x1D,
	0x47, 0x49, 0x5B, 0x55, 0x7F, 0x71, 0x63, 0x6D,
	0xD7, 0xD9, 0xCB, 0xC5, 0xEF, 0xE1, 0xF3, 0xFD,
	0xA7, 0xA9, 0xBB, 0xB5, 0x9F, 0x91, 0x83, 0x8D
};

/*
 * Initialize the given AES-256 encryption context with the given key.
 */

	void
_gst_aes256_init (

struct _gst_aes256_context *	context,
const int8u *			key
)
{
int		i, n;
int8u		rcon, byte;

	rcon = 0x01;
	n = sizeof (context -> key);
	for (i = 0; i < n; i++) {
		byte = key [i];
		context -> encryption_key [i] = byte;
		context -> decryption_key [i] = byte;
	}
	for (i = 0; i < 7; i++) {
		aes256_ExpandEncryptionKey (context -> decryption_key, &rcon);
	}
}

/*
 * Encrypt a block of plaintext using AES-256 in Electronic Code Book mode.
 */

	void
_gst_aes256_encrypt_ecb (

struct _gst_aes256_context *	context,
int8u *				buffer
)
{
int		i;
int8u		rcon;
int8u *		subkey;

	aes256_AddRoundKey_and_copy (buffer,
				     context -> encryption_key,
				     context -> key);
	rcon = 0x01;
	for (i = 1; i < 14; i++) {
		aes256_SubBytes (buffer);
		aes256_ShiftRows (buffer);
		aes256_MixColumns (buffer);

		/* Get next subkey from key schedule. */
		if ((i & 1) NE 0) {
			subkey = &(context -> key [16]);
		}
		else {
			aes256_ExpandEncryptionKey (context -> key, &rcon);
			subkey = &(context -> key [0]);
		}
		aes256_AddRoundKey (buffer, subkey);
	}
	aes256_SubBytes (buffer);
	aes256_ShiftRows (buffer);
	aes256_ExpandEncryptionKey (context -> key, &rcon); 
	aes256_AddRoundKey (buffer, context -> key);
}

/*
 * Decrypt a block of ciphertext using AES-256 in Electronic Code Book mode.
 */

	void
_gst_aes256_decrypt_ecb (

struct _gst_aes256_context *	context,
int8u *				buffer
)
{
int		i;
int8u		rcon;
int8u *		subkey;

	aes256_AddRoundKey_and_copy (buffer,
				     context -> decryption_key,
				     context -> key);
	aes256_inverse_ShiftRows (buffer);
	aes256_inverse_SubBytes (buffer);

	rcon = 0x80;
	for (i = 14; --i;) {
		/* Get next subkey from key schedule. */
		if ((i & 1) NE 0) {
			aes256_ExpandDecryptionKey (context -> key, &rcon);
			subkey = &(context -> key [16]);
		}
		else {
			subkey = &(context -> key [0]);
		}
		aes256_AddRoundKey (buffer, subkey);

		aes256_inverse_MixColumns (buffer);
		aes256_inverse_ShiftRows (buffer);
		aes256_inverse_SubBytes (buffer);
	}
	aes256_AddRoundKey (buffer, context -> key);
}

/*
 * Clear out the given cipher context block.
 */

	void
_gst_aes256_clear (

struct _gst_aes256_context *	context
)
{
int		i, n;
int8u *		p;

	n = sizeof (*context);
	p = (int8u *) context;
	for (i = 0; i < n; i++) {
		*p++ = 0;
	}
}

/*
 * The encryption key schedule.
 * Computes the next 256 bits of the expanded key.
 */

	static
	inline
	void
aes256_ExpandEncryptionKey (

int8u *			key,
int8u *			rconPtr
)
{
int		i;
int8u		rcon;

	rcon = *rconPtr;

	key [0] ^= rijndael_sbox [key [29]] ^ rcon;
	key [1] ^= rijndael_sbox [key [30]];
	key [2] ^= rijndael_sbox [key [31]];
	key [3] ^= rijndael_sbox [key [28]];
	rcon = update_rcon_encrypt (rcon);
	*rconPtr = rcon;

	for (i = 4; i < 16; i += 4) {
		key [i + 0] ^= key [i - 4];
		key [i + 1] ^= key [i - 3];
		key [i + 2] ^= key [i - 2];
		key [i + 3] ^= key [i - 1];
	}
	key [16] ^= rijndael_sbox [key [12]];
	key [17] ^= rijndael_sbox [key [13]];
	key [18] ^= rijndael_sbox [key [14]];
	key [19] ^= rijndael_sbox [key [15]];

	for (i = 20; i < 32; i += 4) {
		key [i + 0] ^= key [i - 4];
		key [i + 1] ^= key [i - 3];
		key [i + 2] ^= key [i - 2];
		key [i + 3] ^= key [i - 1];
	}
}

/*
 * The decryption key schedule.
 * Computes the next 256 bits of the expanded key.
 */

	static
	inline
	void
aes256_ExpandDecryptionKey (

int8u *		key,
int8u *		rconPtr
)
{
int		i;
int8u		rcon;

	rcon = *rconPtr;

	for (i = 28; i > 16; i -= 4) {
		key [i + 0] ^= key [i - 4];
		key [i + 1] ^= key [i - 3];
		key [i + 2] ^= key [i - 2];
		key [i + 3] ^= key [i - 1];
	}

	key [16] ^= rijndael_sbox [key [12]];
	key [17] ^= rijndael_sbox [key [13]];
	key [18] ^= rijndael_sbox [key [14]];
	key [19] ^= rijndael_sbox [key [15]];

	for (i = 12; i > 0; i -= 4) {
		key [i + 0] ^= key [i - 4];
		key [i + 1] ^= key [i - 3];
		key [i + 2] ^= key [i - 2];
		key [i + 3] ^= key [i - 1];
	}

	rcon = update_rcon_decrypt (rcon);
	*rconPtr = rcon;

	key [0] ^= rijndael_sbox [key [29]] ^ rcon;
	key [1] ^= rijndael_sbox [key [30]];
	key [2] ^= rijndael_sbox [key [31]];
	key [3] ^= rijndael_sbox [key [28]];
}

/*
 * The AddRoundKey step, but make a copy of the full 32-byte key also.
 */

	static
	inline
	void
aes256_AddRoundKey_and_copy (

int8u *		buffer,
const int8u *	key,
int8u *		key_copy
)
{
int		i;
int8u		byte;

	for (i = 0; i < 16; i++) {
		byte = key [i];
		buffer [i]   ^= byte;
		key_copy [i] =  byte;

		key_copy [i + 16] = key [i + 16];
	}
}

/*
 * The AddRoundKey step.
 */
	static
	inline
	void
aes256_AddRoundKey (

int8u *		buffer,
const int8u *	key
)
{
int		i;

	for (i = 0; i < 16; i++) {
		buffer [i] ^= key [i];
	}
}

/*
 * The SubBytes step.  (Performs byte substitution using the S-box.)
 */

	static
	inline
	void
aes256_SubBytes (

int8u *		buffer
)
{
int		i;

	for (i = 0; i < 16; i++) {
		buffer [i] = rijndael_sbox [buffer [i]];
	}
}

/*
 * The inverse SubBytes step.  (Inverse of SubBytes operation.)
 */

	static
	inline
	void
aes256_inverse_SubBytes (
int8u *		buffer
)
{
int		i;

	for (i = 0; i < 16; i++) {
		buffer [i] = rijndael_inverse_sbox [buffer [i]];
	}
}

/*
 * The ShiftRows step.
 */

	static
	inline
	void
aes256_ShiftRows (
int8u *		buffer
)
{
int8u		temp;

	/* Row 1 [0,4,8,12]: leave unchanged. */

	/* Row 2 [1,5,9,13]: Rotate 1 position to the left. */
	temp	    = buffer [1];
	buffer [1]  = buffer [5];
	buffer [5]  = buffer [9];
	buffer [9]  = buffer [13];
	buffer [13] = temp;

	/* Row 3 [2,6,10,14]: Rotate 2 positions to the left. */
	temp	    = buffer [2];
	buffer [2]  = buffer [10];
	buffer [10] = temp;
	temp	    = buffer [6];
	buffer [6]  = buffer [14];
	buffer [14] = temp;

	/* Row 4 [3,7,11,15]: Rotate 3 positions to the left. */
	temp	    = buffer [3];
	buffer [3]  = buffer [15];
	buffer [15] = buffer [11];
	buffer [11] = buffer [7];
	buffer [7]  = temp;
}

/*
 * The inverse ShiftRows step.
 */

	static
	inline
	void
aes256_inverse_ShiftRows (

int8u *		buffer
)
{
int8u		temp;

	/* Row 1 [0,4,8,12]: leave unchanged. */

	/* Row 2 [1,5,9,13]: Rotate 1 position to the right. */
	temp	    = buffer [1];
	buffer [1]  = buffer [13];
	buffer [13] = buffer [9];
	buffer [9]  = buffer [5];
	buffer [5]  = temp;

	/* Row 3 [2,6,10,14]: Rotate 2 positions to the right. */
	temp	    = buffer [2];
	buffer [2]  = buffer [10];
	buffer [10] = temp;
	temp	    = buffer [6];
	buffer [6]  = buffer [14];
	buffer [14] = temp;

	/* Row 4 [3,7,11,15]: Rotate 3 positions to the right. */
	temp	    = buffer [3];
	buffer [3]  = buffer [7];
	buffer [7]  = buffer [11];
	buffer [11] = buffer [15];
	buffer [15] = temp;
}

/*
 * The MixColumns step.
 */

	static
	inline
	void
aes256_MixColumns (

int8u *		buffer
)
{
int		i;
int8u		a0, a1, a2, a3;
const int8u	*x2, *x3;

	x2 = &rijndael_times_2 [0];
	x3 = &rijndael_times_3 [0];

	for (i = 0; i < 16; i += 4) {
		a0 = buffer [i + 0];
		a1 = buffer [i + 1];
		a2 = buffer [i + 2];
		a3 = buffer [i + 3];
		buffer [i + 0] = x3 [a1] ^ x2 [a0] ^ a2 ^ a3;
		buffer [i + 1] = x3 [a2] ^ x2 [a1] ^ a3 ^ a0;
		buffer [i + 2] = x3 [a3] ^ x2 [a2] ^ a0 ^ a1;
		buffer [i + 3] = x3 [a0] ^ x2 [a3] ^ a1 ^ a2;
	}
}

/*
 * The inverse MixColumns step.
 */

	static
	inline
	void
aes256_inverse_MixColumns (

int8u *		buffer
)
{
int		i;
int8u		b0, b1, b2, b3;
const int8u	*x9, *x11, *x13, *x14;

	x9  = &rijndael_times_9 [0];
	x11 = &rijndael_times_11 [0];
	x13 = &rijndael_times_13 [0];
	x14 = &rijndael_times_14 [0];

	for (i = 0; i < 16; i += 4) {
		b0 = buffer [i + 0];
		b1 = buffer [i + 1];
		b2 = buffer [i + 2];
		b3 = buffer [i + 3];
		buffer [i + 0] = x14 [b0] ^ x11 [b1] ^ x13 [b2] ^ x9 [b3];
		buffer [i + 1] = x14 [b1] ^ x11 [b2] ^ x13 [b3] ^ x9 [b0];
		buffer [i + 2] = x14 [b2] ^ x11 [b3] ^ x13 [b0] ^ x9 [b1];
		buffer [i + 3] = x14 [b3] ^ x11 [b0] ^ x13 [b1] ^ x9 [b2];
	}
}

/*
 * Compute the next rcon value for encryption.
 */

	static
	inline
	int8u
update_rcon_encrypt (

int8u		rcon
)
{
	return (rijndael_times_x (rcon));
}

/*
 * Compute the next rcon value for decryption.
 */

	static
	inline
	int8u
update_rcon_decrypt (

int8u		rcon
)
{
	return (rijndael_times_x_inverse (rcon));
}

/*
 * Multiply the given polynomial by x, and reduce the result
 * modulo P(x) = x^8 + x^4 + x^3 + x + 1.
 *
 * We use this to successively update the `rcon' value during encryption.
 */

	static
	inline
	int8u
rijndael_times_x (

int8u		poly		/* IN: polynomial to update */
)
{
	if ((poly & 0x80) NE 0) {
		poly <<= 1;
		poly ^= 0x1b;		/* P(x) mod x^8 */
	}
	else {
		poly <<= 1;
	}
	return (poly);
}

/*
 * Multiply the given polynomial by 1/x, and reduce the result
 * modulo P(x) = x^8 + x^4 + x^3 + 1.		[P(x) is 0x11B in binary.]
 *
 * Let Q(x) = x^7 + x^3 + x^2 + 1.		[Q(x) is 0x8D in binary.]
 *
 * Note the following:
 *	1. P(x) is irreducible over Z_2[x].
 *	2. 1 == 1 * P(x) + x * Q(x) (mod 2)
 *	   ===> x * Q(x) == 1 (mod P(x), 2)
 *	   ===> Q(x) == 1/x (mod P(x), 2).
 */

	static
	inline
	int8u
rijndael_times_x_inverse (

int8u		poly		/* IN: polynomial to update */
)
{
	if ((poly & 0x1) NE 0) {
		poly >>= 1;
		poly ^= 0x8D;		/* Q(x) */
	}
	else {
		poly >>= 1;
	}
	return (poly);
}
